Revolution engine

ABSTRACT

Engine for producing mechanical energy by internal combustion of a fuel includes a shaft and a crank arm attached to the shaft. The engine further includes a casing, where the interior of the casing forms a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity and the crank arm is capable of making a seal with the interior surface of the casing to block fluid passage. The interior of the casing also includes a bypass area that allows fluid passage around the crank arm. A first valve is positioned adjacent to the bypass area and a second valve is positioned adjacent to the bypass area opposite from the first valve. The first valve and the second valve are configured to block fluid passage when closed.

BACKGROUND 1. The Field of the Invention

The present invention generally relates to engines. More specifically, the present invention relates to internal combustion engines.

2. The Relevant Technology

An internal combustion engine is an engine where the combustion of a fuel occurs within a chamber to generate force, thus converting chemical energy into mechanical energy. Internal combustion engines are essential to transportation, being heavily utilized in automobiles, aircrafts, boats, and ships. Many power tools and heavy-duty equipment, such as those used for construction and earthwork operations, also rely on internal combustion engines. The most commonly found internal combustion engines operate by the combustion of a fuel inside a cylinder to produce force on a piston. The piston moves in a reciprocating motion and is connected to a crankshaft that converts the reciprocating linear energy into rotational energy capable of spinning a wheel or propeller. Alternatively, a Wankel engine, also known as a rotary engine, utilizes a rotor that has a Reuleaux triangle shape, which rotates inside of an oval/epitrochoid shaped housing to create rotational energy.

BRIEF SUMMARY

In one embodiment, an engine for producing mechanical energy by internal combustion of a fuel includes a shaft and a crank arm attached to the shaft. The engine further includes a casing. The interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity and the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage. The interior of the casing also includes a bypass area that allows fluid passage around the crank arm. A first valve is positioned adjacent to the bypass area, the first valve being configured to block fluid passage when closed. A second valve is positioned adjacent to the bypass area opposite from the first valve. The second valve is also configured to block fluid passage when closed.

In another embodiment, a system for producing mechanical energy by internal combustion of a fuel includes a shaft and a crank arm attached to the shaft. The system further includes a casing. The interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity and the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage. The interior of the casing also includes a bypass area that allows fluid passage around the crank arm. A first valve is positioned adjacent to the bypass area, the first valve being configured to block fluid passage when closed. A second valve is positioned adjacent to the bypass area opposite from the first valve. The second valve is also configured to block fluid passage when closed.

In a different embodiment, an apparatus for producing mechanical energy by internal combustion of a fuel includes a shaft and a crank arm attached to the shaft. The apparatus further includes a casing. The interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity and the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage. The interior of the casing also includes a bypass area that allows fluid passage around the crank arm. A first valve is positioned adjacent to the bypass area, the first valve being configured to block fluid passage when closed. A second valve is positioned adjacent to the bypass area opposite from the first valve. The second valve is also configured to block fluid passage when closed.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures. In the appended figures, similar components or features may have the same reference label.

FIG. 1 is a cutaway diagram of one embodiment of a revolution engine.

FIG. 2 is a cutaway diagram of the revolution engine at the start of the intake phase of the thermodynamic cycle.

FIG. 3 is a cutaway diagram of the revolution engine at the middle of the intake phase.

FIG. 4 is a cutaway diagram of the revolution engine at the end of the intake phase.

FIG. 5 is a cutaway diagram of the revolution engine at the start of the compression phase.

FIG. 6 is a cutaway diagram of the revolution engine at the end of the compression phase.

FIG. 7 is a cutaway diagram of the revolution engine at the start of the power phase.

FIG. 8 is a cutaway diagram of the revolution engine at the end of the power phase.

FIG. 9 is a cutaway diagram of the revolution engine at the start of the exhaust phase.

FIG. 10 is a cutaway diagram of the revolution engine at the middle of the exhaust phase.

FIG. 11 is a cutaway diagram of the revolution engine at the end of the exhaust phase.

FIG. 12 shows an angled perspective of the revolution engine.

FIG. 13 is a cutaway diagram of another embodiment of a revolution engine.

DETAILED DESCRIPTION OF THE INVENTION

The ensuing description provides preferred exemplary embodiments only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the preferred exemplary embodiments will provide those skilled in the art with an enabling description for implementing multiple embodiments with various combinations of the functions and features described herein.

Motors and engines play a critical role in the development of humanity and technological advancement. From construction and transportation to robotics and electronics, industries rely on electric motors and internal combustion engines to perform work and complete tasks that humans cannot or does not want to do. However, current technology has drawbacks that limit efficiency or convenience. For example, piston engines can only achieve an efficiency of around 30 to 40 percent, mainly due to energy loss that occurs when a piston stops and moves in the opposite direction at the top or bottom of the stroke. While Wankel engines are more efficient than piston engines, there is still power loss because the rotor moves eccentrically, and therefore energy is lost when the direction of motion of the rotor changes. Furthermore, additional energy is lost in Wankel engines due to imperfect sealing caused by different operating temperatures in the chamber sections. Electric motors can achieve efficiencies of greater than 90%. However, electric motors are inconvenient in use due to the charging times required for the batteries. Additionally, batteries have an extremely high environmental impact because of the toxic and hazardous chemicals that are used to make the batteries. Furthermore, there are still inefficiencies in generating the electricity that is used to charge the batteries since most generators burn fuel to generate electricity.

The embodiments described herein below overcome the disadvantages of the prior art by providing an internal combustion engine that achieves higher efficiencies while operating by the combustion of fuels, including clean burning and renewable fuels. The engine produces power by rotating a crank arm in concentric revolutions, as opposed to the eccentric motion of the rotor in a Wankel engine or the reciprocating linear motion of pistons. Thus, there is no energy loss due to changing direction of motion and power is conserved. This provides the best of both worlds, achieving the efficiencies of electric motors while providing the conveniences and cleanliness of internal combustion engines. The concentric rotational motion of the engine also greatly reduces vibration, enabling more revolutions per minute and greater power output. Furthermore, the engine is smaller in size and lighter in weight than prior art solutions, facilitating applications where piston engines are not suitable and batteries add too much weight, such as robotics and toys.

FIG. 1 is a cutaway diagram of one embodiment of a revolution engine 100. Engine 100 includes a casing 102 that has a cylindrical shape with a protrusion on the curved surface. Engine 100 also includes a shaft 104, which is the drive shaft that provides rotational output force. Shaft 104 is positioned at the center of the circular cross section of the cylindrical portion of casing 102 and the length of shaft 104 is oriented perpendicular to the circular cross section of casing 102 (aligned along the z-axis of FIG. 1). Shaft 104 is supported by casing 102 and can spin freely independent of casing 102. Crank arm 106 is attached to shaft 104 so that when crank arm 106 rotates, shaft 104 also rotates at the same rate. Crank arm 106 is dimensioned so that the length from the center of the ring shaped section to the tip of crank arm 106 is equal to the radius of the cylindrical shaped hollow cavity 108 formed by the interior of casing 102. Thus, crank arm 106 is able to rotate within hollow cavity 108 while extending to the interior surface of casing 102 to form a seal that can block fluid passage (including gas). To allow room for expansion and contraction, springs and a seal can be attached to the end of crank arm 106 where the crank arm 106 meets casing 102. It should be noted that the seal formed by crank arm 106 and casing 102 does not have to be a perfect seal. Thus, some leakage is acceptable as long as most of the fluid is blocked from passing between crank arm 106 and casing 102.

The protrusion on casing 102 forms an internal bypass area 110 that is connected to the cylindrical shaped hollow cavity 108. In other words, there is nothing separating bypass area 110 from the cylindrical shaped hollow cavity 108. Also, the bypass area 110 is not a separate chamber from hollow cavity 108 and there are no valves separating bypass area 110 from hollow cavity 108. Rather, the bypass area 110 is an extension of the hollow cavity 108. Thus, hollow cavity 108 minus the area of the shaft 104 forms a toroidal shaped cavity within which the crank arm 106 rotates and blocks fluid passage. More specifically, crank arm 106 comprises a heel portion (which has the profile of a ring shape) and a nose portion (which has the profile of a triangular shape with a rounded corner protruding from the ring). Hollow cavity 108 minus the area of the heel of crank arm 106 forms a toroidal shaped cavity within which the nose of crank arm 106 revolves and blocks fluid passage. Bypass area 110 is an extension of the toroidal shaped cavity and spans less than the full 360 degrees of the toroidal shaped cavity. When the nose of crank arm 106 revolves to the position of the bypass area 110, as shown in FIG. 1, fluid is able to pass around crank arm 106 through the bypass area 110. The size of bypass area 110 can be adjusted to change the compression ratio of engine 100, by varying the height or the angle of the span of bypass area 110. In this embodiment, the bypass area 110 spans 36 degrees with minimal height, giving engine 100 a compression ratio of 10:1. The top side of bypass area 110 is curved in this embodiment. However, in other embodiments, the top side can be flat or be formed from two straight lines that join at an angle (making an upside down “v” shape).

A compression valve 112 and a power valve 114 are positioned adjacent to the bypass area 110, the compression valve 112 being on the opposite side of the bypass area 110 from the power valve 114. When compression valve 112 and power valve 114 are in the closed position, as shown in FIG. 1, the valves 112 and 114 form a seal with crank arm 106 (or shaft 104, if the crank arm 106 does not fully encompass the shaft 104, but rather only extends from it). Thus, the valves 112 and 114 block fluid passage from the area in between the valves 112 and 114, which includes the bypass area 110 and a portion of the toroidal shaped cavity (the portion adjacent to the bypass area 110), to the rest of the toroidal shaped cavity when the valves 112 and 114 are closed. Compression valve 112 and power valve 114 are not positioned to block fluid passage from the bypass area 110 to the hollow cavity 108. When valves 112 and 114 are open, fluid is able to pass through the respective valve from the area between valves 112 and 114 (including bypass area 110) to the rest of the toroidal shaped cavity formed between casing 102 and crank arm 106.

Compression valve 112 and power valve 114 are oriented such that the valves 112 and 114 move towards the center of the circular cross section of hollow cavity 108 when the valves 112 and 114 are closing. In other words, compression valve 112 and power valve 114 are positioned along radius lines of the circular cross section of hollow cavity 108 when the valves 112 and 114 are closed. Crank arm 106 has the profile of a cam lobe and is shaped like a cam. Thus, crank arm 106 operates the compression valve 112 and the power valve 114 by pushing the respective valve open as the crank arm 106 rotates past the valve. The two edges on the side of the compression/power valves 112 and 114 that makes the seal with the crank arm 106 are rounded to facilitate smoother opening. Compression valve 112 and power valve 114 can also have ball bearings on the sides for easier opening and there can be grooves in casing 102 that the valves 112 and 114 are positioned between to strengthen the valves 112 and 114 when the valves 112 and 114 are closed. The cam shape of the crank arm 106 allows the seal between the valves 112 and 114 and the crank arm 106 to be maintained while the valves are opening or closing.

Engine 100 also includes an exhaust valve 116 and an intake valve 118. Exhaust valve 116 is positioned to allow fluid to pass from the bypass area 110 to the external of engine 100 and intake valve 118 is positioned to allow fluid passage from the external of engine 100 to the bypass area 110. Camshaft 120 includes two cams, an exhaust cam and a compression cam and camshaft 122 also includes two cams, an intake cam and a power cam. The exhaust cam on camshaft 120 is configured to operate exhaust valve 116 and the intake cam on camshaft 122 is configured to operate intake valve 118. In other embodiments, valves 116 and 118 can be operated by actuators. The compression cam on camshaft 120 operates compression valve lock 124 through push-rod 128 and the power cam on camshaft 122 operates power valve lock 126 through push rod 130. When the compression cam on camshaft 120 pushes against push-rod 128, lock 124 engages to keep compression valve 112 locked in the open position, after the compression valve 112 is opened by crank arm 106. The power cam on camshaft 122 moves push-rod 130 to engage lock 126, which keeps power valve 114 locked in the open position, after the power valve 114 is opened by crank arm 106. Engine 100 is configured such that shaft 104 and crank arm 106 spins four revolutions to complete a cycle, thus the camshafts 120 and 122, as well as the cams, rotate one revolution for every four revolutions of the shaft 104 and crank arm 106. Although omitted from the figure for the sake of clarity, it is understood that there are springs to return the valves 112, 114, 116, and 118 to the closed position when not being opened by crank arm 106 or the cams. There are also springs to return the locks 124 and 126 to the disengaged (i.e., not locking) position when not being acted on by the cams. Engine 100 further includes a spark plug 132 that is positioned to produce sparks in the bypass area 110 in this embodiment, but spark plug 132 can be omitted for diesel applications where ignition is activated by compression instead of a spark.

FIG. 2 is a cutaway diagram of the revolution engine 100 at the start of the intake phase of the thermodynamic cycle. Crank arm 106 and camshafts 120 and 122 are all rotating counterclockwise in this configuration. Compression valve 112 is opened by crank arm 106 and the compression cam on camshaft 120 has just moved push-rod 128 to engage lock 124 to keep compression valve 112 open. Power valve 114 is closed, and lock 126 is not engaged because the power cam on camshaft 122 is not pushing against push-rod 130. Exhaust valve 116 is also closed. Intake valve 118 has just been opened by the intake cam on camshaft 122 to allow the charge (air or air-fuel mixture) to enter the internal of engine 100 as the crank arm 106 continues rotating counterclockwise.

FIG. 3 is a cutaway diagram of the revolution engine 100 at the middle of the intake phase. Crank arm 106 has rotated further and drawn more charge into the internal cavity of engine 100. Compression valve 112 is still held in the open position by lock 124, which is engaged by push-rod 128 and the compression cam on camshaft 120. Power valve 114 remains in the closed position while lock 126 is disengaged and push-rod 130 is not moved by the power cam on camshaft 122. Exhaust valve 116 remains in the closed position and intake valve 118 is fully opened by the intake cam on camshaft 122.

FIG. 4 is a cutaway diagram of the revolution engine 100 at the end of the intake phase. Compression valve 112 is still held in the open position by lock 124, which is engaged by push-rod 128 and the compression cam on camshaft 120. Crank arm 106 has pushed open power valve 114 and the power cam on camshaft 122 has just engaged lock 126 by moving push-rod 130 so that power valve 114 will stay locked in the open position. Exhaust valve 116 remains in the closed position and intake valve 118 has just closed.

FIG. 5 is a cutaway diagram of the revolution engine 100 at the start of the compression phase. Crank arm 106 is at the position of compression valve 112, which is currently in the open position. However, lock 124 is now disengaged because the compression cam on camshaft 120 is no longer pushing on push-rod 128. Thus, compression valve 112 will close as crank arm 106 continues to rotate past the current position. Power valve 114 is still held in the open position by lock 126 since the power cam on camshaft 122 is still pushing on push-rod 130. Exhaust valve 116 and intake valve 118 both remain closed.

FIG. 6 is a cutaway diagram of the revolution engine 100 at the end of the compression phase. Crank arm 106 has rotated 320 degrees from the position depicted in FIG. 5. Since compression valve 112 closed immediately after crank arm 106 moved past the position depicted in FIG. 5, all of the charge has now been compressed to the area between crank arm 106 and compression valve 112, which includes bypass area 110. Power valve 114 is still in the open position, however lock 126 is now disengaged and power valve 114 will close immediately after crank arm 106 moves past the current position depicted in FIG. 6. Exhaust valve 116 and intake valve 118 remain closed.

FIG. 7 is a cutaway diagram of the revolution engine 100 at the start of the power phase. Crank arm 106 is now at the position of compression valved 112. As crank arm 106 moved from the position of power valve 114 (as depicted in FIG. 5) to the current position, the charge was squeezed into the bypass area 110 from between crank arm 106 and compression valve 112. Thus, all of the charge is now behind crank arm 106. Compression valve 112 is held open now by lock 124 while power valve 114 remains closed. Exhaust valve 116 and intake valve 118 also remain closed. Spark plug 132 is activated at this time to produce a spark in the bypass area 110, igniting the charge behind crank arm 106 and causing combustion and expansion, which powers crank arm 106 to rotate counterclockwise. For compression ignition engines that do not have a spark plug, the fuel is injected at this time into the area between crank arm 106 and power valve 114.

FIG. 8 is a cutaway diagram of the revolution engine 100 at the end of the power phase. Crank arm 106 is now at the position of power valve 114 and has pushed power valve 114 open, while lock 126 has just engaged to keep power valve 114 open. Compression valve 112 remains in the open position, held there by lock 124. Exhaust valve 116 and intake valve 118 remain closed.

FIG. 9 is a cutaway diagram of the revolution engine 100 at the start of the exhaust phase. Crank arm 106 is now at the position of the compression valve 112, however lock 124 has just disengaged so compression valve 112 will close immediately after the crank arm 106 rotates past the current position. Power valve 114 is still being held open by lock 126. Exhaust valve 116 has just been opened and intake valve 118 remains closed.

FIG. 10 is a cutaway diagram of the revolution engine 100 at the middle of the exhaust phase. Compression valve 112 is closed and power valve 114 remains open while crank arm 106 continues rotating, pushing exhaust fumes out through exhaust valve 116 that is still in the open position. Intake valve 118 remains closed.

FIG. 11 is a cutaway diagram of the revolution engine 100 at the end of the exhaust phase. Crank arm 106 is at the position of power valve 114, which is open. However, lock 126 has just disengaged so that power valve 114 will close as crank arm 106 continues rotating. Compression valve 112 remains closed. Exhaust valve 116 has just closed and intake valve 118 remains closed. This is the end of the thermodynamic cycle, thus a new iteration of the cycle will begin again after this as depicted in FIG. 2.

FIG. 12 shows an angled perspective of the revolution engine 100. From this perspective, the exhaust cam 134 can be distinguished from the compression cam 136 on camshaft 120. Also, the intake cam 138 can be distinguished from the power cam 140 on camshaft 122.

FIG. 13 is a cutaway diagram of another embodiment of a revolution engine 200. The difference with this embodiment is that crank arm 202 does not operate compression valve 204 and power valve 206. In other words, compression valve 204 and power valve 206 are not pushed open by crank arm 202. Rather, compression valve 204 is opened and closed by compression cam 208 through rocker arm 210 and power valve 206 is opened and closed by power cam 212 through rocker arm 214. This saves wear and tear on crank arm 202 and valves 204 and 206. The shape of the profile of cams 208 and 212 is configured such that the seal that the valves 204 and 206 make with crank arm 202 can be maintained as the valves 204 and 206 are opening and closing. Since each of the compression valve 204 and power valve 206 is open for one revolution of crank arm 202 and closed for the next revolution (although the timing is different for the two valves), cams 208 and 212 rotate one revolution for every two revolutions of crank arm 202. However, it is also possible to setup a 1:4 ratio for the revolution of cams 208 and 212 by using the cam profile from the previous embodiment. Exhaust cam 220 and intake cam 222 still rotate one revolution for every four revolutions of crank arm 202, and exhaust cam 220 still operates exhaust valve 216 while intake cam 222 operates intake valve 218. The difference is that each of the cams 208, 212, 220 and 222 has its own camshaft now. The timing for opening and closing the valves 204, 206, 216 and 218 with respect to the position of crank arm 202 for each phase of the thermodynamic cycle is still the same as described in FIGS. 2-11 for the previous embodiment.

Another feature illustrated in this figure is the balancing of crank arm 202. The crank arm 202 is shaped like a cam, which has a heel and a nose. Thus, crank arm 202 has a ring shaped profile portion (the heel) and a portion with a profile of a triangular shape with a rounded corner such that the rounded corner is protruding out from the ring (the nose). Counterbalance weight 224 is positioned opposite from the nose on the heel to counter the extra weight of the nose so that crank arm 202 spins more smoothly and evenly, which also reduces vibration in engine 200. Counterbalance weight 224 is embedded within crank arm 202 so that no part of the weight 224 is sticking out. Counterbalance weight 224 can be made with a material that is more dense than the material of the crank arm 202, so that the weight is evenly distributed around crank arm 202 even though the nose adds extra volume. Although counterbalance weight 224 is illustrated as rectangular shaped, it is understood that the weighted material can take any shape and can be positioned anywhere within the crank arm 202 to counter balance the weight of the nose. Thus, crank arm 202 is made up of two or more materials with different densities.

A portion of material can also be removed from crank arm 202 to form a cavity 226 in the crank arm 202. Cavity 226 also serves the purpose of providing a more balanced crank arm 202 where the weight is evenly distributed around the axis of rotation. Cavity 226 is positioned across both the nose and the heel of crank arm 202, thus a portion of the weight of the nose has been removed and a portion of the weight of the heel has been removed from crank arm 202. Although cavity 226 is depicted as having a triangular profile with rounded corners, cavity 226 can also be shaped differently to achieve better balance. For example, the profile edge of cavity 226 that is closest to the center can be curved instead of straight. Cavity 226 can be used as an alternative to counterbalance weight 224 or cavity 226 can be used in conjunction with weight 224 so that crank arm 202 has a perfectly balanced weight distribution around its axis of rotation.

While the principles of the disclosure have been described above relating to specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. 

What is claimed is:
 1. An engine for producing mechanical energy by internal combustion of a fuel, the engine comprising: a shaft; a crank arm attached to the shaft; a casing, wherein: an interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity, the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage, and the interior of the casing includes a bypass area that allows fluid passage around the crank arm; a first valve positioned adjacent to the bypass area, wherein the first valve is configured to block fluid passage when closed; and a second valve positioned adjacent to the bypass area opposite from the first valve, wherein the second valve is configured to block fluid passage when closed.
 2. The engine of claim 1, further comprising an exhaust valve configured to control fluid passage to an external of the engine.
 3. The engine of claim 2, wherein the exhaust valve is positioned to allow fluid passage from the bypass area to the external of the engine.
 4. The engine of claim 1, further comprising an intake valve configured to control fluid passage from an external of the engine.
 5. The engine of claim 4, wherein the intake valve is positioned to allow fluid passage from the external of the engine to the bypass area.
 6. The engine of claim 1, wherein the hollow cavity is shaped as a cylinder.
 7. The engine of claim 1, wherein the crank arm rotates concentrically within the hollow cavity.
 8. A system for producing mechanical energy by internal combustion of a fuel, the system comprising: a shaft; a crank arm attached to the shaft; a casing, wherein: an interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity, the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage, and the interior of the casing includes a bypass area that allows fluid passage around the crank arm; a first valve positioned adjacent to the bypass area, wherein the first valve is configured to block fluid passage when closed; and a second valve positioned adjacent to the bypass area opposite from the first valve, wherein the second valve is configured to block fluid passage when closed.
 9. The system of claim 8, wherein the crank arm is shaped such that the crank arm can push the first valve and the second valve open as the crank arm rotates.
 10. The system of claim 8, wherein the first valve and the second valve are configured to form a seal against the crank arm to block fluid passage as the crank arm rotates.
 11. The system of claim 8, further comprising a spark plug.
 12. The system of claim 11, wherein the spark plug is positioned to produce a spark in the bypass area.
 13. The system of claim 8, wherein the first valve is configured to be closed during a compression phase of an operating cycle of the system, and open during a power phase of the operating cycle of the system.
 14. An apparatus for producing mechanical energy by internal combustion of a fuel, the apparatus comprising: a shaft; a crank arm attached to the shaft; a casing, wherein: an interior of the casing includes a hollow cavity dimensioned to allow the crank arm to rotate within the hollow cavity, the crank arm is capable of making a seal with an interior surface of the casing to block fluid passage, and the interior of the casing includes a bypass area that allows fluid passage around the crank arm; a first valve positioned adjacent to the bypass area, wherein the first valve is configured to block fluid passage when closed; and a second valve positioned adjacent to the bypass area opposite from the first valve, wherein the second valve is configured to block fluid passage when closed.
 15. The apparatus of claim 14, further comprising a camshaft that includes a first cam, wherein the first cam is configured to operate an intake valve.
 16. The apparatus of claim 15, wherein the first cam rotates one revolution for every four revolutions of the crank arm.
 17. The apparatus of claim 15, wherein the camshaft further includes a second cam, and wherein the second cam is configured to operate the first valve in conjunction with the crank arm.
 18. The apparatus of claim 17, wherein the second cam operates the first valve by holding the first valve open after the crank arm opens the first valve.
 19. The apparatus of claim 14, wherein the first valve is opened by a cam separate from the crank arm.
 20. The apparatus of claim 19, wherein the cam rotates one revolution for every two revolutions of the crank arm. 